Publications
Filter Total Items: 2573
A large mantle water source for the northern San Andreas Fault System: A ghost of subduction past
Recent research indicates that the shallow mantle of the Cascadia subduction margin under near-coastal Pacific Northwest U.S. is cold and partially serpentinized, storing large quantities of water in this wedge-shaped region. Such a wedge probably formed to the south in California during an earlier period of subduction. We show by numerical modeling that after subduction ceased with the creation o
Authors
Stephen H. Kirby, Kelin Wang, Thomas M. Brocher
Understanding the magnitude dependence of PGA and PGV in NGA-West 2 data
The Next Generation Attenuation‐West 2 (NGA‐West 2) 2014 ground‐motion prediction equations (GMPEs) model ground motions as a function of magnitude and distance, using empirically derived coefficients (e.g., Bozorgniaet al., 2014); as such, these GMPEs do not clearly employ earthquake source parameters beyond moment magnitude (M) and focal mechanism. To better understand the magnitude‐dependent tr
Authors
Annemarie S. Baltay, Thomas C. Hanks
Why the New Madrid earthquakes are M 7–8 and the Charleston earthquake is ∼M 7
Estimates of magnitudes of large historical earthquakes are an essential input to and can seriously affect seismic‐hazard estimates. The earthquake‐intensity observations, modified Mercalli intensities (MMI), and assigned magnitudes Mof the 1811–1812 New Madrid events have been reinterpreted several times in the last decade and have been a source of controversy in making seismic‐hazard estimates i
Authors
Chris H. Cramer, Oliver S. Boyd
Late Holocene slip rate and ages of prehistoric earthquakes along the Maacama Fault near Willits, Mendocino County, northern California
The Maacama fault is the northward continuation of the Hayward–Rodgers Creek fault system and creeps at a rate of 5.7±0.1 mm/yr (averaged over the last 20 years) in Willits, California. Our paleoseismic studies at Haehl Creek suggest that the Maacama fault has produced infrequent large earthquakes in addition to creep. Fault terminations observed in several excavations provide evidence that a pre
Authors
Carol S. Prentice, Martin C. Larsen, Harvey M. Kelsey, Judith Zachariasen
Using the USGS Seismic Risk Web Application to estimate aftershock damage
The U.S. Geological Survey (USGS) Engineering Risk Assessment Project has developed the Seismic Risk Web Application to combine earthquake hazard and structural fragility information in order to calculate the risk of earthquake damage to structures. Enabling users to incorporate their own hazard and fragility information into the calculations will make it possible to quantify (in near real-time) t
Authors
Sean M. McGowan, Nicolas Luco
Metrics for comparing dynamic earthquake rupture simulations
Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction cons
Authors
Michael Barall, Ruth A. Harris
Investigation of the high-frequency attenuation parameter, κ (kappa), from aftershocks of the 2010 Mw 8.8 Maule, Chile earthquake
The Bío Bío region of Chile experienced a vigorous aftershock sequence following the 2010 February 27 Mw 8.8 Maule earthquake. The immediate aftershock sequence was captured by two temporary seismic deployments: the Quake Catcher Network Rapid Aftershock Mobilization Program (QCN RAMP) and the Incorporated Research Institutions for Seismology CHile Aftershock Mobilization Program (IRIS CHAMP). Her
Authors
Corrie Neighbors, E. J. Liao, Elizabeth S. Cochran, G. J. Funning, A. I. Chung, J. F. Lawrence, C. M. Christensen, M. Miller, A. Belmonte, H. H. Andrés Sepulveda
World-Wide Standardized Seismograph Network: a data users guide
The purpose of this report, which is based on an unpublished draft prepared in the 1970s, is to provide seismologists with the information they may need to use the WWSSN data set as it becomes available in a more easily accessible and convenient format on the Internet. The report includes a description of the WWSSN network, station facilities, operations and instrumentation, a derivation of the in
Authors
Jon R. Peterson, Charles R. Hutt
The 2011 Virginia M5.8 earthquake: Insights from seismic reflection imaging into the influence of older structures on eastern U.S. seismicity
The Mineral, Virginia (USA), earthquake of 23 August 2011 occurred at 6– 8 km depth within the allochthonous terranes of the Appalachian Piedmont Province, rupturing an ~N36°E striking reverse fault dipping ~50° southeast. This study used the Interstate Highway 64 seismic refl ection profi le acquired ~6 km southwest of the hypocenter to examine the structural setting of the earthquake. The profi
Authors
Thomas L. Pratt, J. Wright Horton, D.B. Spear, A.K. Gilmer, Daniel E. McNamara
Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part B, historical earthquakes
Computation of probabilistic earthquake hazard requires an estimate of Mmax: the moment magnitude of the largest earthquake that is thought to be possible within a specified geographic region. The region specified in this report is the Central and Eastern United States and adjacent Canada. Parts A and B of this report describe the construction of a global catalog of moderate to large earthquakes t
Authors
Russell L. Wheeler
Holocene earthquakes and right-lateral slip on the left-lateral Darrington-Devils Mountain fault zone, northern Puget Sound, Washington
Sources of seismic hazard in the Puget Sound region of northwestern Washington include deep earthquakes associated with the Cascadia subduction zone, and shallow earthquakes associated with some of the numerous crustal (upper-plate) faults that crisscross the region. Our paleoseismic investigations on one of the more prominent crustal faults, the Darrington–Devils Mountain fault zone, included tre
Authors
Stephen F. Personius, Richard W. Briggs, Alan R. Nelson, Elizabeth R Schermer, J. Zebulon Maharrey, Brian L. Sherrod, Sarah A. Spaulding, Lee-Ann Bradley
The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms
The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribut
Authors
Jeanne L. Hardebeck